As the United States assembles a coalition-of-the-threatened against the ISIL terrorist organization, now is the time to begin planning for the "day after."

ISIL is a new and uniquely disturbing threat to the peoples of the region, its state system, and Western interests in the Middle East and beyond. It controls, or partly controls, an area roughly the size of Belgium across northeast Syria and western Iraq (having dissolved the border in the areas under their rule). The CIA estimates they have up to 31,000 fighters, and their oil revenues alone are thought to bring in $1-2 million a day.

Rarely has a terrorist group assembled such vast resources, and never has one controlled so much territory in the heart of the Arab world. Moreover, ISIL openly proclaims its antagonism to the entire existing Middle Eastern (and ultimately global) state system, which it vows to destroy, and posits itself as a radical alternative.

Because of the rapid, terrifying recent sweep by ISIL out of Syria and into Iraq -- seizing control of key strategic locations and major cities like Mosul -- response has tended to focus on situation-specific and counter-terrorism oriented approaches. This is understandable, and indeed indispensable. Additionally, the nature and impact of the political aspects of the "day after" must be charted now, at the outset of this lengthy and complex process, in order to ensure that they lay the foundations for regional stability and security.

But ISIL is merely one manifestation of a broader phenomenon of violent Islamist extremism that threatens Western interests and mainstream Muslim-majority societies in many parts of the Islamic world, and under many guises. It's not enough to simply treat this symptom, although that is certainly essential. Rather the whole disease of violent religious radicalism, with multiple incarnations across the Islamic world, is rooted in ideology and in the failure of states and the collapse of societies. It must be confronted by a sustained strategy that addresses these root causes.

ISIL's partial obliteration of the Syria-Iraq border is emblematic of the endemic and growing state failure in parts of the Arab world that produced the organization in the first place, and on which it continues to feed. There is a vicious circle of mutual self-reinforcement between state and society failure on the one hand and the rise of extremist non-state actors on the other.

The groundbreaking Arab Human Development Report, issued by the United Nations in 2002, painted a stark, sober and depressing picture of a region in desperate need of development, and social and economic growth. Unfortunately but unsurprisingly, the Report was widely welcomed, but then woefully neglected, with its recommendations languishing in obscurity.

The Report called attention to three crucial requirements for Arab development: human rights and freedoms as the basis for good governance and accountability; the empowerment of women; and improving knowledge acquisition and utilization. Subsequent reports looked at each of these areas in more detail.

The reports did not suggest that a terrorist rampage was the most likely consequence of a failure to address these challenges. For that, the additional brutality of the al-Assad dictatorship, and sectarian misrule by Iraqi governments, were required. But it is state failure, with its disastrous social and political consequences -- as exemplified today in not only Syria and Iraq, but Libya and potentially some other Arab countries as well -- that lies at the heart of the explosion of violent extremism.

The 2002 Report documented how far behind most of the rest of the globe the Arab world had already fallen. The regional picture is now even more dire.

Some Arab states and societies are pressing forward in a process of dynamic globalization, and developing more open relations based on commerce and interdependency on issues ranging from security to the environment, sustainability to public health. Yet most of the Arab world appears to be sliding ever further back into an insular mindset that views the rest of the world, and its cultural and social influences, with suspicion and hostility. Sectarianism, which wasn't even mentioned in the 2002 Report, has become a brutal and bloody incubator of violence across and within many Arab states.

The international community is correctly determined to reverse the rise of ISIL by force. But ultimately armed conflict, counterterrorism and law-enforcement are insufficient to reverse the tide of violent extremism. That requires stemming and redressing the causes of regional and state failure, economic malaise, social alienation and cultural degradation. Only by addressing and resolving these root causes can the region, the international community, and the United States break the cycle of repeated and indecisive wars that merely set the stage for another round of conflict.

The only way to eradicate, not just diminish, movements that thrive in such contexts, taking advantage of weak states and societies, is to rebuild those states and societies. This is the challenge now facing the Middle East. Global powers, in their own self-interests, need to be strategic partners in helping the region prepare for not just the day, but decades, after the defeat of ISIL.